A team from Jiangsu University of Technology, Soochow University, and Ghent University has engineered a transparent, self-healing polyurethane coating that repairs scratches within minutes under heat and simultaneously stops bacterial growth. The material, reported on October 11, 2025, in the Chinese Journal of Polymer Science (DOI:10.1007/s10118-025-3414-7), offers a solution to the common problems of scratches, fouling, and microbial attachment that degrade protective films on devices, marine sensors, and medical equipment.
Polyurethane coatings are widely used to protect cars, ships, electronics, and public-touch surfaces, but real-world exposure leads to scratches, microbial buildup, and loss of transparency. Traditional self-healing films often rely on microcapsules that work only once, while others compromise clarity or lack antibacterial properties. The new coating incorporates dynamic selenonium salts into the polymer network, enabling the material to heal damage while maintaining high transparency and antibacterial function.
In tests, the coating healed visible scratches within one hour at 140 °C, and with slight pressure, recovery time shortened to about 20 minutes. Even after multiple cut-and-remold cycles, the films preserved their chemical structure and mechanical behavior. Antibacterial tests showed that selenonium-containing samples dramatically inhibited E. coli and S. aureus growth, with high-loading formulations nearly eliminating colonies. Scanning electron microscopy revealed ruptured bacterial membranes, indicating a contact-killing mechanism.
The coating also demonstrated excellent optical clarity, with light transmittance of approximately 90–91%, comparable to bare glass. After two weeks of simulated seawater immersion, it remained clear with minimal swelling. Pencil hardness reached 1H and adhesion was rated 4B–5B, meeting standards for protective coatings on devices and marine windows.
The technology could benefit phone screens, touch panels, underwater lenses, public facilities, medical devices, and ship equipment. Its recyclability supports circular material design, and with further development, the coating may help reduce maintenance costs and biofouling in marine or healthcare environments.
